Downfeed continuous pulping apparatus



A ril 21, 1964 L. A. CARLSMITH 3,

DOWNFEED CONTINUOUS PULPING APPARATUS Original Filed May 9, 1960 United States Patent 3,130,119 DOWNFEED CONTINUGUS PULPING APPARATUS Lawrence A. Carlsmith, Amherst, N31, assignor to Ir"- proved Machinery, Inc, Nashua, RH, a corporation of Maine Continuation of application Ser. No. 27,593, May 9, 1960. This application Nov. 29, 1961, Ser. No. 155,681

6 Claims. (Cl. 162-437) This invention relates to continuous pulping apparatus and systems, and is a continuation of application Serial No. 27,593, filed May 9, 1960. More particularly, it relates to novel apparatus for advancing solid particles through a vessel containing a solid particle liquid mixture, movement of the solid particles being controlled independently of the liquid.

It is a major object of the present invention to provide novel apparatus capable of advancing even dry wood chips through a reaction vessel irrespective of the direction of liquid flow therein. This has been accomplished by providing a single solidparticle feeding means at one end of the vessel, which means exerts force only on wood chips or other particles located adjacent said end of the vessel progressively to advance a mass of wood chips filling the vessel beyond such feeding means throughout the length of the vessel. The intermediate portion of the vessel is thus entirely unobstructed for Wood chip advance and for circulation of treating liquids as desired.

For the purpose of explaining further objects and features of the invention, reference is now made to the following detailed description of a preferred embodiment of the invention, taken with the accompanying drawings, wherein:

FIG. 1 is a detailed cross sectional side elevation of downflow apparatus embodying the downfeeding means and discharge means of the invention;

FIG. 2 is a cross sectional plan view showing the downfeeding means of FIG. 1, taken on the line 2-2 thereof; and

FIG. 3 is an isometric detail view of the discharge means of the apparatus of FIG. 1.

In FIGS. 1-3 is shown a pretreatment downflow vessel 20 incorporating the novel downfeeding means of the invention, together with auxiliary apparatus including a chip bin 12 having a screw conveyor means 14 in its bottom for feeding wood chips into the upper end of vessel 20. In general, the infed wood chips are moved downwardly in the form of a compacted mass through vessel 20 while being treated by a suitable liq 'd, are diluted by the discharge means thereof, and are then discharged in dilute form, generally to a succeeding process.

Turning now to the specific pretreatment vessel 28 of FIG. 1, the vessel 2% itself is of generally cylindrical form but preferably slightly tapered to expand in a downward direction say of the order of A to /2 inch per foot of length. In the upper end of the vessel is mounted the downfeeding tamping means as is hereinafter described. Thereabove is a chip inlet opening 21 through which chip conveyor means 14 is enabled to feed chips into the vessel 2%) above said means. An exhaust opening 19 is also provided in the top of the vessel in order to exhaust volative gases, such as turpentine, which may be evolved from the chip mass within the tower. At the bottom of the tower, defining the lower end of the compacted chip mass, spaced a major portion of the vertical length of the vessel below the downfeeding tamping means of the invention, is a discharge means enabling the feeding of chips from the lower end of the chip mass at the same rate that they enter the top, so that a solid particle-liquid mixture may be established in the bottom portion of vessel 20 for feeding to a subsequent reaction vessel. A

liquid inlet 22 is provided at the bottom of the tower below the discharge means and a liquid outlet in the form of strainer 24 adjacent the upper end, as is hereinafter more fully described.

As best shown in FIGS. 1 and 2, the novel downfeeding means of the invention utilized in vessel 20 to insure the downward advance of chips as a compacted mass, comprises a single web-like member mounted adjacent the upper end of the vessel for generally vertical reciprocatory movement having a stroke of, say, about 3 to 24 inches. Preferably, said member includes a vertically arranged central shaft 31 having a plurality of spoke-like operating elements 31, herein shown as four in number, mounted on the lower end of shaft 30 and extending radially thereof with uniform angular spacing. These operating elements 31 provide an interrupted operating surface extending in a horizontal plane for free passage of the wood chips or other solid particles therethrough. The operating elements thus provide a downfeeding and tamping means extending generally throughout the horizontal area of the vessel substantially less than the horizontal sectional area of the vessel, with a working area of about l080 percent of the total vessel area, preferably about 20%.

The shaft 36 is mounted in a suitable bearing 32 near its lower end above elements 31 and at its upper end it carries a piston 36 which operates in a double acting cylinder 35 having suitable fluid inlet means to each chamber thereof as Well as means for supplying fluid to said inlets in a manner to reciprocate the piston at the rate of a few strokes per minute, say 1 to 30, and preferably about 5.

Shaft 39 is also provided with a gear 33 operated by a suitable fluid motor 39, so that the elements 31 may be rotated bodily around shaft 39 as desired. Such rotation may desirably be accomplished on the up stroke and may be through a small increment say about 10 degrees, so that the elements 31 come down at a different place on the chip pole on each reciprocation.

When chips, either in dry form or as a solid-particle liquid mixture, are fed into the vessel above the elements 31, they will tend to flow past and under the elements 31 as the elements lift and then are tamped and fed downwardly by the elements as the elements subsequently complete their downward stroke. The reciprocating tamping action of elements 31 compacts the wood chips or other solid particles as they are fed into the vessel and advances them as a compacted mass downwardly through the vessel. This permits the uniform advance of the wood chips throughout the unobstructed horizontal cross-sectional area of the tower for a major portion of the length thereof for fluid treatment irrespective of the effect of the fluid on the buoyancy of the chips, for example. Thus, if a liquid be employed in which the chips are normally buoyant, the downfeeding means of the invention makes possible the downward advance of the chips, even with countercurrent liquid flow or the generating of steam which would also tend to oppose their advance. Further more, the uniformly compacted mass of chips extending throughout the eifective length of the vessel, as is made possible by the positive downfeed characteristic of the invention, greatly aids in making possible uniform chip treatment, by preventing non-uniform channeling and blockage. This is particularly vital in large diameter vessels.

The discharge means, as is best shown in isometric view in FIG. 3 in addition to being shown in side elevation in FIG. 1, comprises a pair of helical plates 49 having overlapping edges, say, by about 10 to 30 degrees and mounted for rotation at the upper end of a shaft 42, itself being driven by a motor 43. Thus, a double lead screw discharger is provided having a pair of leading edges, which at a speed of say 30 r.p.m. will continuously take a thin slice from the bottom of the compacted mass of chips and so remove the chips from the mass as fast as the mass ad- .vances downwardly through the tower. The speed of the plates and the pitch of their helical form are so proportioned that the thickness of the slice removed from the bottom of the chip mass never exceeds the pitch and the discharger can always accept material as fast as it is moved downwardly. Below the plates 40 within vessel 20 is a zone of a dilute mixture of chips and liquid, of such consistency that can be easily transferred through a conventional pump and pipes into the bottom of a succeeding pressurized reaction vessel, for example. The excess liquid required to operate this dilute zone is fed to the bottom of vessel 20 through inlet 23. The overlapping arrangement of plates 40 insures that if the system is stopped long enough for chips to settle by gravity toward the bottom of vessel 20, the mass will come to rest on plates. 40 rather than filling the lower zone below these plates which might cause plugging in the outlet pipes when restarting.

Liquid inlet 22 is positioned below plates 40 and strainer 24 is positioned near the upper end of the tower below tamping members 31. A pump 27 and heater 25 is provided for recirculating and heating the treating liquid and a valve 26 is connected thereto for adding liquid as it is discharged with the solid particle-liquid mixture. If desired, a level sensing means 45 may be employed to sense the preferred level of the liquid above strainer 24 and below tamping members 31 as shown in FIG. 1, and such level sensing means may be operatively connected to valve 46 to control the balance of fluid into vessel 20 through pipe 47 and inlet 23 so as to maintain a constant level. As shown, the flow of impregnating liquid is countercurrent, as is preferred for countercurrent heating and for deaerating in a wood chip pulping process, but by utilizing a strainer at the lower opening 22 co-current flow may be used.

Thus it will be seen that the invention provides novel apparatus for feeding a vessel. Various modifiactions of the invention within the spirit thereof and the scope of the appended claims will be apparent to those skilled in this art.

What is claimed is:

1. Apparatus for continuously treating the solid particle component of a solid particle-liquid mixture in a generally upright elongated reaction vessel having inlet means for feeding solid particles into said vessel adjacent the upper end thereof and discharge means for discharging said mixture from said vessel adjacent the bottom of said vessel, that improvement which consists of down-feeding means for advancing the solid particle component thereof downwardly through said vessel substantially independently of the movement of liquid in said vessel, including a solid particle downfeeding member mounted adjacent the upper end of said vessel for generally vertical reciprocatory movement, said member having a plurality of spokelike operating elements with relatively flat bottoms providing an interrupted surface extending in a horizontal plane for free passage of said solid particles therethrough, means for feeding said solid particles into said vessel above said elements, hydraulic means including piston and cylinder means for reciprocating said member through a limited distance relatively to the length of said vessel to advance said particles downwardly by exerting force only on particles located adjacent the upper end of said vessel progressively to compact said particles and to advance the mass of said particles downwardly through said vessel, liquid supply means adjacent the bottom of said vessel for supplying liquid thereto for upward flow thereof through said descending particles, and strainer means spaced upwardly from said liquid supply means and below the said spoke-like operating elements for removing liquid from said vessel.

2. Apparatus as claimed in claim 1, further including means for rotating said downfeeding member about a vertical axis.

3. Apparatus as claimed in claim 1 wherein the horizontal area of said downfeeding member is about 10-80 percent of the total horizontal area of said vessel.

4. Apparatus for continuously treating the solid particle component of a solid particle-liquid mixture in'a generally upright vertically elongated vessel having inlet means for feeding solid particles into said'vessel adjacent the upper end thereof and discharge means for discharging said mixture from said vessel adjacent the lower end thereof, that improvemnet which consists of downfeedin'g means for advancing the solid particle component of said mixture through said vessel substantaillyindependently of the movement of liquid in said vessel, said downfeeding means including a single solid particle downfeeding member having a plurality of spoke-like operating ele ments with relatively flat bottoms providing an interrupted surface extending in a horizontal plane with a working horizontal sectional area substantially less than the horizontal sectional area of said vessel for free passage of said solid particles through said surface, said member being mounted for generally vertical reciprocatory'movement adjacent the upper end of said vessel spaced above said discharge means a major portion of the length of said vessel providing an unobstructed vessel cross 'sectional area therebetween, means for reciprocating said member through a limited distance relatively to the length of said vessel to advance said particles through said vessel toward the lower end thereof by exerting advancing force only on particles located adjacent the upper end of said vessel below the surface of said member, progressively to compact said particles and to advance the mass of said particles through said vesel toward the lower end thereof and liquid supply means for supplying liquid to said vessel.

5. Apparatus as claimed in claim 4 wherein the working area of said member is about 10 to percent of the area of said vessel.

6. Apparatus as claimed in claim 4, further including means for rotating said member.

References Cited in the file of this patent UNITED STATES PATENTS 

1. APPARATUS FOR CONTINUOUSL TREATING THE SOLID PARTICLE COMPONENT OF A SOLID PARTICLE-LIQUID MIXTURE IN A GENERALLY UPRIGHT ELONGATED REACTION VESSEL HAVING INLET MEANS FOR FEEDING SOLID PARTICLES INTO SAID VESSEL ADJACENT THE UPPER END THEREOF AND DISCHARGE MEANS FOR DISCHARGING SAID MIXTURE FROM SAID VESSEL ADJACENT THE BOTTOM OF SAID VESSEL, THAT IMPROVEMENT WHICH CONSISTS OF DOWN-FEEDING MEANS FOR ADVANCING THE SOLID PARTICLE COMPONENT THEREOF DOWNWARDLY THROUGH SAID VESSEL SUBSTANTIALLY INDEPENDENTLY OF THE MOVEMENT OF LIQUID IN SAID VESSEL, INCLUDING A SOLID PARTICLE DOWNFEEDING MEMBER MOUNTED AJACENT THE UPPER END OF SAID VESSEL FOR GENERALLY VERTICAL RECIPROCATORY MOVEMENT, SAID MEMBER HAVING A PLURALITY OF SPOKELIKE OPERATING ELEMENTS WITH RELATIVELY FLAT BOTTOMS PROVIDING AN INTERRUPTED SURFACE EXTENDING IN A HORIZONTAL PLANE FOR FREE PASSAGE OF SAID SOLID PARTICLES THERETHROUGH, MEANS FOR FEEDING SAID SOLID PARTICLES INTO SAID VESSEL ABOVE SAID ELEMENTS, HYDRAULIC MEANS INCLUDING PISTON AND CYLINDER MEANS FOR RECIPROCATING SAID MEMBER THROUGH A LIMITED DISTANCE RELATIVELY TO THE LENGTH OF SAID VESSEL TO ADVANCE SAID PARTICLES DOWNWARDLY BY EXERTING FORCE ONLY ON PARTICLES LOCATED ADJACENT THE UPPER END OF SAID VESSEL PROGRESSIVELY TO COMPACT SAID PARTICLES AND TO ADVANCE THE MASS OF SAID PARTICLES DOWNWARDLY THROUGH SAID VESSEL, LIQUID SUPPLY MEANS ADJACENT THE BOTTOM OF SAID VESSEL FOR SUPPLYING LIQUID THERETO FOR UPWARD FLOW THEREOF THROUGH SAID DESCENDING PARTICLES, AND STRAINER MEANS SPACED UPWARDLY FROM SAID LIQUID SUPPLY MEANS A ND BELOW THE SAID SPOKE-LIKE OPERATING ELEMENTS FOR REMOVING LIQUID FROM SAID VESSEL. 